ITEM NAME:4-channel 250VAC 30A Solid State Relay Module Board High/Low Level Trigger B7V2 4-channel 250VAC 30A Solid State Relay Module Board High/Low Level Trigger B7V2 250V 30A high quality solid state relay. Input power supply: DC 5V or AC 100-250V isolation module(not included). Has been assembled and more convenient for wiring. High/low level can be set freely. Great for electronics hobbyist to do DIY work. Type: 4-channel Control Load: 250V 30A Power Supply: DC 5V (can also use AC 100-250V isolation module for power supply) Trigger Type: High/Low Level Trigger Input Control Signal Voltage: 0-1V Low Level, the Relay OFF; 1.5-5V High Level, the Relay ON Wiring Port Description: DC +: positive(this interface can be used for high level trigger if you use isolation module for power) DC-: negative CH1.CH2...: trigger terminal Item Size: 4-channel: 143 x 60 x 20.5mm Item Weight: 4-channel: 178g / 6.27oz Package List: 1 x Relay Module Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm..250V 30A high quality solid state relay. Trigger Type: High/Low Level Trigger. DC +: positive(this interface can be used for high level trigger if you use isolation module for power). 0-1V Low Level, the Relay OFF;.